What do the following two equations represent? $-x-y = 4$ $-5x-5y = 20$
Solution: Putting the first equation in $y = mx + b$ form gives: $-x-y = 4$ $-y = x+4$ $y = -1x - 4$ Putting the second equation in $y = mx + b$ form gives: $-5x-5y = 20$ $-5y = 5x+20$ $y = -1x - 4$ The above equations turn into the same equation, so they represent equal lines.